Make each bpf() syscall command a bit more self-contained, making it
easier to further enhance it. We move sysctl_unprivileged_bpf_disabled
handling down to map_create() and bpf_prog_load(), two special commands
in this regard.
Also swap the order of checks, calling bpf_capable() only if
sysctl_unprivileged_bpf_disabled is true, avoiding unnecessary audit
messages.
Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
---
kernel/bpf/syscall.c | 37 ++++++++++++++++++++++---------------
1 file changed, 22 insertions(+), 15 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 14f39c1e573e..d5009fafe0f4 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1132,6 +1132,17 @@ static int map_create(union bpf_attr *attr)
int f_flags;
int err;
+ /* Intent here is for unprivileged_bpf_disabled to block key object
+ * creation commands for unprivileged users; other actions depend
+ * of fd availability and access to bpffs, so are dependent on
+ * object creation success. Capabilities are later verified for
+ * operations such as load and map create, so even with unprivileged
+ * BPF disabled, capability checks are still carried out for these
+ * and other operations.
+ */
+ if (sysctl_unprivileged_bpf_disabled && !bpf_capable())
+ return -EPERM;
+
err = CHECK_ATTR(BPF_MAP_CREATE);
if (err)
return -EINVAL;
@@ -2504,6 +2515,17 @@ static int bpf_prog_load(union bpf_attr *attr, bpfptr_t uattr, u32 uattr_size)
char license[128];
bool is_gpl;
+ /* Intent here is for unprivileged_bpf_disabled to block key object
+ * creation commands for unprivileged users; other actions depend
+ * of fd availability and access to bpffs, so are dependent on
+ * object creation success. Capabilities are later verified for
+ * operations such as load and map create, so even with unprivileged
+ * BPF disabled, capability checks are still carried out for these
+ * and other operations.
+ */
+ if (sysctl_unprivileged_bpf_disabled && !bpf_capable())
+ return -EPERM;
+
if (CHECK_ATTR(BPF_PROG_LOAD))
return -EINVAL;
@@ -5004,23 +5026,8 @@ static int bpf_prog_bind_map(union bpf_attr *attr)
static int __sys_bpf(int cmd, bpfptr_t uattr, unsigned int size)
{
union bpf_attr attr;
- bool capable;
int err;
- capable = bpf_capable() || !sysctl_unprivileged_bpf_disabled;
-
- /* Intent here is for unprivileged_bpf_disabled to block key object
- * creation commands for unprivileged users; other actions depend
- * of fd availability and access to bpffs, so are dependent on
- * object creation success. Capabilities are later verified for
- * operations such as load and map create, so even with unprivileged
- * BPF disabled, capability checks are still carried out for these
- * and other operations.
- */
- if (!capable &&
- (cmd == BPF_MAP_CREATE || cmd == BPF_PROG_LOAD))
- return -EPERM;
-
err = bpf_check_uarg_tail_zero(uattr, sizeof(attr), size);
if (err)
return err;
--
2.34.1
